vmcoreinfo: fix the configuration dependencies

This patch fixes the configuration dependencies in the vmcoreinfo data.

i386's "node_data" is defined in arch/x86/mm/discontig_32.c,
and x86_64's one is defined in arch/x86/mm/numa_64.c.
They depend on CONFIG_NUMA:
  arch/x86/mm/Makefile_32:7
    obj-$(CONFIG_NUMA) += discontig_32.o
  arch/x86/mm/Makefile_64:7
    obj-$(CONFIG_NUMA) += numa_64.o

ia64's "pgdat_list" is defined in arch/ia64/mm/discontig.c,
and it depends on CONFIG_DISCONTIGMEM and CONFIG_SPARSEMEM:
  arch/ia64/mm/Makefile:9-10
    obj-$(CONFIG_DISCONTIGMEM) += discontig.o
    obj-$(CONFIG_SPARSEMEM)    += discontig.o

ia64's "node_memblk" is defined in arch/ia64/mm/numa.c,
and it depends on CONFIG_NUMA:
  arch/ia64/mm/Makefile:8
    obj-$(CONFIG_NUMA)         += numa.o

Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Acked-by: Simon Horman <horms@verge.net.au>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>